People who are blind or visually impaired often rely on their other senses to help compensate for their lack of sight. A visually impaired person may, for example, rely on the sound of his shoes striking the floor to identify rooms, doorways, and objects in the vicinity. Similarly, a visually impaired pedestrian may use the sound and frequency of engine noise to determine the location, speed, and direction of motor vehicles when walking near roadways.
With interest in environmentally-friendly sources of energy and the desire to reduce dependence on foreign oil on the rise, the number of battery electric vehicles (BEVs) and hybrid-electric vehicles (HEVs) on the road is increasing. Because BEVs and HEVs are powered, at least part of the time, by an electric motor rather than a combustion engine, such vehicles do not produce as much noise as conventional, gas-powered vehicles. These quiet vehicles may be more difficult for a visually impaired person to detect and navigate around as compared to conventional vehicles and, as a result, may present a greater risk of harm to the visually impaired. To avoid such dangers posed by quiet-running vehicles, some visually impaired individuals may need help from other people or may have to avoid certain activities all together. As a result, some visually impaired individuals may lose some of their independence, which may detract from their quality of life.
Thus, there is a need for a system that provides a pedestrian with a warning when a vehicle is near without causing prolonged periods of noise that would disrupt other people in the area.